The investigators request for the purchase of a small animal radiator, Mark I Cesium Irradiator model 68, to support NIH funded research in stem cell biology, stem cell transplantation and cancer. This request is timely because the seven investigators who will use this radiator have recently moved into the Wolstein Research Building of Case School of Medicine, CWRU. This building is not linked by internal passageways to the major animal facility of the Case School of Medicine or two sites housing current radiation equipment. Since radiation of mice and rats is an essential element to the NIH funded research of the requesting investigators, this piece of equipment will greatly enhance the ability to conduct animal research in a timely fashion. The irradiator will be housed within the twenty-eight thousand-cage clean barrier facility located in the sub-basement of the Wolstein Research Building. The radiator will be managed, as part of the Case Comprehensive Cancer Center Radiation Resource. All investigators housed in the Wolstein Building will utilize this facility for animal research. By placing the irradiator within the facility, it will be possible to maintain animals for prolonged periods of time without exposing these animals to pathogens in the environment. Currently no comparable piece of equipment is located within the Case School of Medicine that is accessible to these investigators. For this reason this is a high priority and its request for an essential piece of equipment to support the research of NIH funded investigators.